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					<h1>CodeIgniter User Guide Version 2.0.3</h1>
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		<h1>CAPTCHA Helper</h1>

		<p>The CAPTCHA Helper file contains functions that assist in
			creating CAPTCHA images.</p>


		<h2>Loading this Helper</h2>

		<p>This helper is loaded using the following code:</p>
		<code>$this->load->helper('captcha');</code>

		<p>The following functions are available:</p>

		<h2>
			create_captcha(
			<var>$data</var>
			)
		</h2>

		<p>Takes an array of information to generate the CAPTCHA as input
			and creates the image to your specifications, returning an array of
			associative data about the image.</p>

		<code>
			[array]<br /> (<br /> &nbsp;&nbsp;'image' => IMAGE TAG<br />
			&nbsp;&nbsp;'time' => TIMESTAMP (in microtime)<br />
			&nbsp;&nbsp;'word' => CAPTCHA WORD<br /> )
		</code>

		<p>
			The "image" is the actual image tag:
			<code>&lt;img
				src=&quot;http://example.com/captcha/12345.jpg&quot;
				width=&quot;140&quot; height=&quot;50&quot; /&gt;</code>
		</p>

		<p>The "time" is the micro timestamp used as the image name
			without the file extension. It will be a number like this:
			1139612155.3422</p>

		<p>The "word" is the word that appears in the captcha image, which
			if not supplied to the function, will be a random string.</p>

		<h3>Using the CAPTCHA helper</h3>

		<p>Once loaded you can generate a captcha like this:</p>

		<code>
			$vals = array(<br /> &nbsp;&nbsp;&nbsp;&nbsp;'word' => 'Random
			word',<br /> &nbsp;&nbsp;&nbsp;&nbsp;'img_path' => './captcha/',<br />
			&nbsp;&nbsp;&nbsp;&nbsp;'img_url' => 'http://example.com/captcha/',<br />
			&nbsp;&nbsp;&nbsp;&nbsp;'font_path' => './path/to/fonts/texb.ttf',<br />
			&nbsp;&nbsp;&nbsp;&nbsp;'img_width' => '150',<br />
			&nbsp;&nbsp;&nbsp;&nbsp;'img_height' => 30,<br />
			&nbsp;&nbsp;&nbsp;&nbsp;'expiration' => 7200<br />
			&nbsp;&nbsp;&nbsp;&nbsp;);<br /> <br /> $cap =
			create_captcha($vals);<br /> echo $cap['image'];
		</code>

		<ul>
			<li>The captcha function requires the GD image library.</li>
			<li>Only the img_path and img_url are required.</li>
			<li>If a "word" is not supplied, the function will generate a
				random ASCII string. You might put together your own word library
				that you can draw randomly from.</li>
			<li>If you do not specify a path to a TRUE TYPE font, the native
				ugly GD font will be used.</li>
			<li>The "captcha" folder must be writable (666, or 777)</li>
			<li>The "expiration" (in seconds) signifies how long an image
				will remain in the captcha folder before it will be deleted. The
				default is two hours.</li>
		</ul>

		<h3>Adding a Database</h3>

		<p>
			In order for the captcha function to prevent someone from submitting,
			you will need to add the information returned from
			<kbd>create_captcha()</kbd>
			function to your database. Then, when the data from the form is
			submitted by the user you will need to verify that the data exists in
			the database and has not expired.
		</p>

		<p>Here is a table prototype:</p>

		<code>
			CREATE TABLE captcha (<br /> &nbsp;captcha_id bigint(13) unsigned
			NOT NULL auto_increment,<br /> &nbsp;captcha_time int(10) unsigned
			NOT NULL,<br /> &nbsp;ip_address varchar(16) default '0' NOT NULL,<br />
			&nbsp;word varchar(20) NOT NULL,<br /> &nbsp;PRIMARY KEY
			`captcha_id` (`captcha_id`),<br /> &nbsp;KEY `word` (`word`)<br />
			);
		</code>

		<p>Here is an example of usage with a database. On the page where
			the CAPTCHA will be shown you'll have something like this:</p>

		<code>
			$this-&gt;load-&gt;helper(&#x27;captcha&#x27;);<br /> $vals = array(<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&#x27;img_path&#x27; =&gt;
			&#x27;./captcha/&#x27;,<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&#x27;img_url&#x27; =&gt;
			&#x27;http://example.com/captcha/&#x27;<br />
			&nbsp;&nbsp;&nbsp;&nbsp;);<br /> <br /> $cap =
			create_captcha($vals);<br /> <br /> $data = array(<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&#x27;captcha_time&#x27; =&gt;
			$cap[&#x27;time&#x27;],<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&#x27;ip_address&#x27; =&gt;
			$this-&gt;input-&gt;ip_address(),<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&#x27;word&#x27; =&gt; $cap[&#x27;word&#x27;]<br />
			&nbsp;&nbsp;&nbsp;&nbsp;);<br /> <br /> $query =
			$this-&gt;db-&gt;insert_string(&#x27;captcha&#x27;, $data);<br />
			$this-&gt;db-&gt;query($query);<br /> <br /> echo &#x27;Submit the
			word you see below:&#x27;;<br /> echo $cap[&#x27;image&#x27;];<br />
			echo &#x27;&lt;input type=&quot;text&quot; name=&quot;captcha&quot;
			value=&quot;&quot; /&gt;&#x27;;
		</code>

		<p>Then, on the page that accepts the submission you'll have
			something like this:</p>

		<code>
			// First, delete old captchas<br /> $expiration = time()-7200; //
			Two hour limit<br /> $this-&gt;db-&gt;query(&quot;DELETE FROM
			captcha WHERE captcha_time &lt; &quot;.$expiration); <br /> <br />
			// Then see if a captcha exists:<br /> $sql = &quot;SELECT COUNT(*)
			AS count FROM captcha WHERE word = ? AND ip_address = ? AND
			captcha_time &gt; ?&quot;;<br /> $binds =
			array($_POST[&#x27;captcha&#x27;], $this-&gt;input-&gt;ip_address(),
			$expiration);<br /> $query = $this-&gt;db-&gt;query($sql, $binds);<br />
			$row = $query-&gt;row();<br /> <br /> if ($row-&gt;count == 0)<br />
			{<br /> &nbsp;&nbsp;&nbsp;&nbsp;echo &quot;You must submit the word
			that appears in the image&quot;;<br /> }
		</code>
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